Abstract:
Three forms (micellar solution, emulsion and liposome) of water-based antibacterial products were formulated using peppermint oil (PO) as active ingredient. Food grade emulsifiers were polyoxyethylene (20) sorbitan monolaurate (Tween 20) for micellar solution and emulsion, and soy lecithin for liposome. The results showed that transparent micellar solutions with volume moment mean diameter, D[4,3], less than 10 nm could be formulated at PO concentrations of ≤ 5 and ≤ 8 %wt in 25 and 30 %wt Tween 20 solution, respectively. The higher content of PO resulted in oil-in-water emulsions with D[4,3] of 3-5 m. Emulsion could not form at PO > 9 %wt. Liposome could be formulated using 8-23 %wt PO with 0.7 %wt soy lecithin. Liposome aggregates had D[4,3] of 1-5 m. Antibacterial activity (in term of clear zone diameter, Dc) for pure PO was found to be 17.68, 14.78 and 12.32 mm for Lactobacillus sp. TISTR539, Staphylococcus aureus ATCC25923 and Escherichia coli ATCC25922, respectively. For the formulated products, the minimum PO concentrations of 8, 7 and 5 %wt were required for inhibition (Dc ≥ 8 mm) of Lactobacillus sp., S. aureus and E. coli, respectively. For Pseudomonas aeruginosa ATCC9027, pure PO did not show antibacterial activity, but the formulated products (micelle solution of ≥ 7 %wt PO, emulsion of ≥ 8 %wt PO and liposome of 23 %wt PO) had antibacterial activity. Selected the liposome content 23 % of PO incorporated with carboxymethyl cellulose solution for form the antibacterial biodegradable film. That results the film was clear thickness between 0.02-0.2 mm elongation value 0.4-9 % tensile strength between 0.2-37 MPa and water vapor permeability rate 0.4-3 (10-⁶ g m /m² d) and were not found the antibacterial activity of any film products.